This invention relates to televisions, and more particularly to digital televisions capable of picture enhancement as well as picture in picture processing.
Digital televisions incorporating advanced features are now known in the art. While different digital televisions incorporate different features such as multiple picture in picture processing, picture enhancement processing (e.g. freeze, store and recall picture processing, noise reduction, and cross-color effect reduction), and progressive scan processing (e.g. median filtering, etc.), none of the televisions in the art are known to provide all three processing features.
In providing a picture in picture (PIP) process, a processing block obtains a secondary source of digital video, and processes the main video signal such that the secondary video source data is displayed as a small picture within the main picture. If desired, multiple PIPs can be produced. With multiple PIPs, typically all but one of the smaller pictures are frozen and a large amount of memory is required to store the frozen frames.
In freezing, storing, and recalling a main picture, video data must be retained and returned to the processor so that the frozen picture may be displayed. Thus, a large memory which is often comprised of charged coupled devices (CCD) or dynamic RAMs (DRAM) is typically utilized for this purpose (i.e. to feed stored data to the processor). If instead of freezing, storing and recalling a main picture, it is desirable to effect noise reduction and/or cross-color reduction (picture enhancement), the same second large memory is often utilized as a field delay. With a field delay, implementation may be had of a first order recursive filter that can accomplish noise reduction. Likewise, by adding the color data from a video line delayed by the field memory to color data from a current video line, cross-color effects may be reduced. Cross color effects are also known to be somewhat reduced by the recursive filter used for reducing noise.
In the progressive scanning process which produces a non-interlaced display by interpolating and inserting an extra line between current video lines, a large memory is required. The most effective progressive scan algorithm, median filtering, requires field delayed data, and a separate memory means for delaying the field has been provided in the past in conjunction with any progressive scan processor.
While picture in picture, picture enhancement, and progressive scan processing are all known, they have not all been utilized together. One possible reason for the failure to combine technologies is the large amount of memory required for each process, and the resulting expense.